What is "impossible constraint in `asm'" when building

Hi, all

I’m beginner for embedded linux development, so have many problems. --;

I want to cross compile SDL for my embedded linux device using mips.
(In my pure linux box, I have confirmed build OK)
Toolchains for mips have been installed and I have tried cross compiled.
And error messages just like below appeared._______________________________
mipsel-linux-cc -g -O2
-I./include -D_GNU_SOURCE=1 -I/usr/include/kde/artsc -pthread
-I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -I/usr/include
-DXTHREADS -I/usr/local/include/directfb -D_REENTRANT -D_REENTRANT
-DHAVE_LINUX_VERSION_H -c ./src/audio/dma/SDL_dmaaudio.c -fPIC -DPIC -o
./src/audio/dma/SDL_dmaaudio.c: In function DMA_WaitAudio': ./src/audio/dma/SDL_dmaaudio.c:166: error: impossible constraint inasm’
make: *** [build/SDL_dmaaudio.lo] Error 1

What is "impossible constraint in `asm’"
The line which makes error have ‘FD_ZERO(&fdset);’

In addition, I wonder that I gave some wrong option when running
(CC, LD and other variables are set.) Here is my confiure command and
./configure --build=mipsel-linux target=mipsel-linux

Please, give me some advise.

Thanks in advance.